so, unmetered air gets into the stream somewhere after the carb plates but before the combustion chambers. so any vacuum valve, hose, tube switch diaphram that feeds into the intake stream post throttle plate can be the culprit. it can be the gaskets, or insulator itself, the intake manifold gaskets or the gasket between the intake and the exhaust, or any of the VCV, or VSVs or VTVs or their hoses. You need to use your propane torch to look for where it could be getting in. you can also try to systemically cap off all sources to vacuum components till you get a notible change in idle quality. once you can eliminate unmetered air, you can begin to dial in your carb settings...if you can't hold a 700 rpm idle after warm, you have an intake vacuum leak, and you need to fix it first.
